2

Component of semen.:
The ejaculate, or semen, is made up of sperm from the testicles & fluids from the seminal vesicles, the prostate, and the bulbourethral glands. The seminal fluid is a viscous fluid rich in fructose, making up the bulk of semen. The prostate adds a thin white fluid containing enzymes, citric acid, and lipids. The bulbourethral glands add a clear fluid. Ejaculation is the act of discharging semen.
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3

400 million:
During ejaculation about 400 million sperm are released in the man has a normal sperm count. There are about 5 million sperm in preejaculatory fluid which is why the pullout method is not advised.
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5

Yep, it's possible:
This is a great little summary: http://plannedparenthood.tumblr.com/post/59218535396/whats-the-average-concentration-of-sperm-in-pre-cum. But don't forget to think about STDs as well. Pre-ejaculate can be the source of HCV, HBV, HIV, Chlamydia, Gonorrhea, etc. Penile skin can be the source of HSV (herpes), syphilis, HPV (warts & cervical cancer)...bottom line: plan & know your partner very well.
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6

Yes, :
Yes, any contact with seminal fluid can result in pregnancy, even after only a few seconds of penetration. If the patient has any concern for pregnancy, they should take a test if their period is late at all, and if it is negative but the period still doesn't start then wait two days and retake the test. If it is still negative, but the patient doesn't get their period, then she should see a doctor for a blood pregnancy test. The patient should also be seen if there is any concern about sexually transmitted infection.
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